To use or not to use defog in camera housings.

[Dee]

How/when do I use the no-fog that came with the housing?

I wouldn't use it at all. Use silica gel dessicant paks instead. I buy mine from Preserve Smart. If the no-fog stuff works, all it does is address the result, not the cause of the fogging. Like using de-fog in your mask, it doesn't eliminate it, it just keeps the condensation off the glass. That condensation will collect as water drops and that's the last thing you want inside your housing.

The condensation (fog) is a result of the inside of the housing getting warmer than the outside environment from the heat of your camera and the result is a condensation of the humidity inside the housing. Just like your car windows fogging up in the winter. The dessicant paks will absorb the moisture inside the housing. That doesn't mean it will absorb water, it won't. I'm talking about the humidity moisture. The dessicant paks I buy have a small window in the back where you can see the crystals turn from blue when it's fresh to pink when it's spent. You can then revitalize them in a low oven for a few hours.

 

[armyscuba]

I use Silica packs in My Reefmaster Dee..They work great in this Cuban Humidity...otherwise forget it..the housing fogs in minutes. The Air temp is over 100 and the water is 82 degrees at 130 ft...I put the camera together in an A/C room and take it out..I have not had a problem yet..but others I dive with have had many problems..started doing the same thing..and have enjoyed the same success..

 

[jonnythan]

I put some defog on the inside of the camera housing glass when I got it, and have reapplied it every few months since. I also keep a silica packet in it when diving.. one of the benefits of working at an outdoor gear store is lots of access to silica (The North Face packs almost everything with it).

 

[miketsp]

I use Silica Gel packs. I first dry them out by putting them in contact with a normal incandescent lamp for a couple of hours. Anything in the range 40W to 100W. The advantage is that this is a dry heat and works just as well when you are in a hotel room - not always do you have access to an oven or time for the air conditioner to lower the humidity and wait for bags to dry. I have several sets and after drying roll them up tightly in plastic bags. Each time I have to open a housing on the boat (eg to change batteries) I throw in a couple of new dry bags.

 

[pdoege]

Canon includes a tube of the stuff. I use the silica packs too. I also assemble in an AC area.

Peter

 

[miketsp]

Just a couple of comments about silica gel.

The recommended temperature for regeneration is heating it above 300 degrees F (150 C).

Also

Since we tend to keep reusing our silica gel packs we should avoid the self indicating type. There is a move away from this traditional self-indicating silica gel following European Commission Directive 98/98/EC (amendment to 67/548/EEC) reclassifying cobalt chloride as a potential carcinogen by inhalation.
When we keep reusing the same packs the friction on the crystals keeps increasing the amount of dust in the packs.

 

[armyscuba]

Just a couple of comments about silica gel.

The recommended temperature for regeneration is heating it above 300 degrees F (150 C).

Also

Since we tend to keep reusing our silica gel packs we should avoid the self indicating type. There is a move away from this traditional self-indicating silica gel following European Commission Directive 98/98/EC (amendment to 67/548/EEC) reclassifying cobalt chloride as a potential carcinogen by inhalation.
When we keep reusing the same packs the friction on the crystals keeps increasing the amount of dust in the packs.

Interesting...What is meant by Regeneration? does it reclaim the silica at heat above 300 degrees?

 

[IndyScott]

I have been having fogging problems and have ordered some silica packs, I hope they work. Scott

 

[jcclink]

If using self indicating gel packs its obvious when they need to be replaced. Otherwise its sorta guess work. Do you change them every day? Leave them in until you get fogging? (then its too late) If you're on a trip, you probably don't have access to an oven. Since I've been using the indicating packs in my PT-015, I find that about 3 days is the useful life. It also depends on size & number of packs you use. The government will eventually tell us that everything causes cancer, so personally I'm not overly concerned.

 

[Dee]

Interesting...What is meant by Regeneration? does it reclaim the silica at heat above 300 degrees?

It just means the absorbed moisture has been removed and the silica packs can be reused like new.

The packs that I buy are only about 30¢ each so if you don't want to rejuvenate them endlessly, they are cheap enough to throw away after just a few uses. I like the color indicators so I know when to change them.